Garyville climate

Garyville Frost Dates and Growing Season

NOAA 1991-2020 normals for Reserve, 3.7 km from Garyville, elevation 15 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Reserve. A median date has an even chance of a later freeze in spring, or an earlier one in fall.

The last spring freeze typically comes around February 9 and the first fall freeze around December 14, a growing season of about 308 days.

Median at 36°F
last February 27, first November 28
Median at 32°F
last February 9, first December 14
Median at 28°F
last January 28, first January 1

Last freeze in spring

The chance of a later freeze than the date shown. At 10 percent, one spring in ten still freezes after the date; planting after the 10 percent date for 32°F is the cautious choice.

Threshold10%20%30%40%50%60%70%80%90%
36°FMar 22Mar 14Mar 8Mar 2Feb 27Feb 22Feb 17Feb 10Feb 1
32°FMar 11Mar 1Feb 24Feb 17Feb 9Feb 3Jan 30Jan 24Jan 13
28°FFeb 26Feb 15Feb 6Jan 31Jan 28Jan 21Jan 16Jan 6Dec 28
24°FFeb 9Feb 1Jan 29Jan 24Jan 19Jan 14Jan 10Jan 2Dec 26
20°FFeb 4Feb 1Jan 27Jan 22Jan 19Jan 14Jan 11Jan 8Jan 4
16°F–––––––––

First freeze in fall

The chance of an earlier freeze than the date shown. At 10 percent, one fall in ten freezes before the date.

Threshold10%20%30%40%50%60%70%80%90%
36°FNov 8Nov 14Nov 19Nov 24Nov 28Dec 1Dec 6Dec 11Dec 22
32°FNov 21Nov 29Dec 3Dec 8Dec 14Dec 21Dec 29Jan 3Jan 13
28°FDec 2Dec 12Dec 20Dec 28Jan 1Jan 5Jan 11Jan 18Feb 1
24°FDec 19Dec 28Jan 1Jan 4Jan 9Jan 12Jan 18Jan 26Feb 4
20°FJan 1Jan 5Jan 9Jan 11Jan 13Jan 17Jan 21Jan 27Feb 1
16°F–––––––––

Growing season length

Days between the last spring and first fall freeze at each threshold, with the chance of a season at least that long.

Threshold10%20%30%40%50%60%70%80%90%
36°F307296287280275268263254244
32°F345334325315308300292283272
28°F365365359350342336329317304
24°F365365365365365365357345334
20°F365365365365365365365365360
16°F365365365365365365365365365

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder
100% of years
32°F or colder
97% of years
28°F or colder
79% of years
24°F or colder
41% of years
20°F or colder
13% of years
16°F or colder
4% of years

Degree days

A degree day is one degree of the daily mean temperature beyond a base, for one day. Heating degree days count cold (the fuel a house burns), cooling degree days heat, growing degree days the warmth a crop needs; each crop has its own base.

Heating degree days, base 65°F
1,342
Cooling degree days, base 65°F
2,870
Growing degree days, base 40°F
10,666
Growing degree days, base 45°F
8,884
Growing degree days, base 50°F
7,171
Growing degree days, base 55°F
5,576
Growing degree days, base 60°F
4,131

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January3906153
February24915214
March13953388
April39145557
May2329792
June0478928
July05631,028
August05631,028
September0440889
October29213651
November17047338
December32519206

What this means

NOAA computes these from the daily lows at the station over 1991-2020, fitting the dates of each year's last and first freeze to a distribution, so a date can be stated at any level of risk. 36°F is a frost risk for tender plants on a clear, calm night, since the ground cools below the air above it; 32°F is a freeze; 28°F is a hard freeze that kills most annuals.

The station is 3.7 km from Garyville. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00167767 (Reserve). Public domain.